Subject: How to support non-LAN DLCs

From: "almost, but not quite, entirely unlike tea 07-Jul-1993 0909 -0400" <[email-masked]>
Date: Wed, 7 Jul 93 09:08:04 EDT

Just to kick this off, I'd like peoples opinion on just exactly the best way
to handle SDLC specifically: maybe this is simple-minded, but I have been
assuming that the way to do this is to assign a MAC Address & SAP to each
SDLC station (which means that for an SDLC-to-SDLC type connection, two MAC
Addresses/SAP pairs are assigned).

The definition of an SDLC station in the router to which it is directly attached
would then contain the MAC Address/SAP for that station, and optionally the
MAC Address/SAP of the system to which it is defined to be connected - if the
MAC Addr/SAP of the other station is not defined, then communication can not
be initiated by that SDLC station.

For example (SAPs left off for clarity):

                          +------+
              +------+   /        \   +------+
    +----+    |Router|  /   IP     \  |Router|    +---+
    | 20 |----|  A   |-+  Network   +-|  B   |----|NCP|
    +----+    |      |  \          /  |      |    +---+
              +------+   \        /   +------+
                          +------+
        Local MAC Addr=1                 Local MAC Addr=2
        Dest  MAC Addr=2                 Dest  MAC Addr=1

If either Router did not have the destination defined, then it could not 
initiate CANUREACH processing to find the destination, and frames received 
from the attached SDLC station would simply be dropped.

This exact same approach also works unchanged (I think!) for the SDLC-to-LLC 
case.

However, this all seems too simple and obvious - I must be missing something ;-)

Simon

PS: Regarding adding QLLC to the list of possibilities - I have to question
	the real value of this: can anyone really justify it (other than for
	completeness?) Also, if we do decide to add QLLC, then we should
	presumably add all combinations, including QLLC-to-QLLC which was not
	listed in Bernie's message